Patch the various recently reported security vulnerabilities in Mozilla.
This is being done instead of the update to 1.0 PR 1 since we're in a ports
freeze, and too many big changes is not a good idea.
This update covers the following Mozilla bugs:
250862
255067
256316
Thanks to nectar for scraping all of these patches together.
Obtained from: Mozilla CVS
Approved by: portmgr (implicit)